Antenna



FIG. 1 is a front plan view of an antenna according to the present invention;

FIG. 2 is a rear plan view thereof; and,

FIG. 3 is a front plan view of the antenna of FIG. 1 in use.

The broken lines in FIG. 3 illustrate environment and form no part of the claimed design. 

CLAIM The ornamental design for an antenna, as substantially shown and described. 